Free Developer Tools Tools
Free developer tools for engineers, DevOps practitioners, and technical teams who need reliable utilities without leaving the browser. Format and validate JSON, encode and decode Base64 strings and files, compare code changes with a line-by-line diff, generate cryptographically secure passwords, decode JWT tokens, test regular expressions with live highlighting, and generate UUIDs — all running locally with no data leaving your device.
These utilities handle the tiny-but-essential tasks that break your flow when you have to Google for them or spin up a local script. Bookmark this page and keep shipping. Every tool is free forever, requires no account, and works offline once cached.
25 free tools available now
Password Generator
Generate secure, random passwords instantly
JSON Formatter
Format, validate, and minify JSON instantly
Base64 Encoder / Decoder
Encode and decode Base64 text and files instantly
Text Diff Checker
Compare two texts and highlight the differences instantly
CSV to JSON Converter
Convert CSV files to clean JSON instantly — free, private, no upload
JSON to CSV Converter
Convert JSON arrays to CSV — free, private, instant download
UUID Generator
Generate UUIDs v1, v4 & v7 instantly in your browser
Regex Tester
Test and debug regular expressions with live match highlighting
JWT Decoder
Decode and inspect JWT tokens — header, payload, claims, expiry
Unit Converter
Convert between length, weight, temperature, volume, area, speed, and data units
Color Contrast Checker
Check WCAG color contrast ratios for accessible web design
Hash Generator
Generate MD5, SHA-1, SHA-256, and SHA-512 hashes from text or files
CSS Gradient Generator
Build beautiful CSS gradients visually and copy the code instantly
URL Encoder / Decoder
Encode and decode URLs — encodeURIComponent, encodeURI, and Base64 modes
JSON to TypeScript
Convert any JSON to TypeScript interfaces instantly
Pomodoro Timer
Focus timer with work, short break, and long break sessions
Cron Expression Generator
Build and parse cron expressions with a visual editor
CSS Minifier & Beautifier
Minify or beautify CSS instantly in your browser
HTML Encoder / Decoder
Encode and decode HTML entities instantly
YAML to JSON Converter
Convert YAML to JSON and JSON to YAML — bidirectional, no upload
Epoch & Unix Timestamp Converter
Convert Unix timestamps to dates and back — seconds, milliseconds, or microseconds
Image to Base64 Converter
Convert any image to a Base64 data URI with ready-to-paste CSS and HTML
JSON Diff & Compare
Compare two JSON documents and see exactly what changed
SQL Formatter & Beautifier
Format and beautify SQL in 10 dialects — instantly and privately
CSV Cleaner & Deduplicator
Remove duplicate rows, trim whitespace, and clean up any CSV
All free developer tools tools
Every tool listed below is 100% free, requires no account, and runs entirely in your browser — your data never leaves your device.
🔐 Free Password Generator
Generate strong, cryptographically secure passwords instantly. Choose length up to 64 chars, character types — up to 10 at once. Never sent anywhere. Free, no signup.
🔧 Free JSON Formatter
Free JSON formatter and validator. Paste messy JSON to instantly format, validate, and highlight errors. Supports minify, indent options, and copy. No signup required.
🔢 Free Base64 Encoder / Decoder
Free Base64 encoder and decoder. Encode text or files to Base64 and decode Base64 strings back to text. Supports file to data URI encoding. No signup required.
🔍 Free Text Diff Checker
Free text diff checker. Paste two blocks of text to instantly see what was added, removed, or changed line by line. Great for comparing documents, code, or any text. No signup required.
📋 Free CSV to JSON Converter
Free CSV to JSON converter. Paste or upload any CSV file and get clean, formatted JSON in seconds. Auto-detects delimiter, handles headers, supports large files. 100% in-browser, no signup.
🔄 Free JSON to CSV Converter
Free JSON to CSV converter. Paste or upload a JSON array of objects and download a clean CSV in seconds. Handles nested objects with dot-notation flattening. 100% in-browser, no signup.
🆔 Free UUID Generator
Free UUID generator. Generate version 1, 4, and 7 UUIDs in bulk — individually or as a JSON / newline list. Runs 100% in your browser. No signup, no server.
🔣 Free Regex Tester
Free online regex tester with live match highlighting, capture groups, named groups, and full flag support. Supports JavaScript (ECMAScript) regex syntax. No signup required.
🔓 Free JWT Decoder
Free JWT decoder. Paste any JSON Web Token to instantly see the decoded header, payload claims, expiry status, and signature. 100% browser-side — your token never leaves your device.
⚖️ Free Unit Converter
Free unit converter. Convert length (cm to inches, km to miles), weight (kg to lbs), temperature (Celsius to Fahrenheit), volume, area, speed, and digital data units. Fast, accurate, no signup.
🎨 Free Color Contrast Checker
Free WCAG color contrast checker. Enter foreground and background colors to instantly see the contrast ratio and whether it passes WCAG 2.1 AA and AAA standards for normal and large text. No signup.
# Free Hash Generator
Free hash generator. Generate MD5, SHA-1, SHA-256, SHA-384, and SHA-512 cryptographic hashes from text or files. Verify file integrity and checksums instantly in your browser. No upload, no signup.
🌈 Free CSS Gradient Generator
Free CSS gradient generator. Build linear, radial, and conic gradients visually — add color stops, set positions and angles — and copy the ready-to-use CSS. No signup.
🔗 Free URL Encoder / Decoder
Free URL encoder and decoder. Encode special characters for safe use in URLs, query strings, or HTML. Decode percent-encoded URLs instantly. Supports encodeURIComponent, encodeURI, and Base64. No signup.
🟦 Free JSON to TypeScript
Free JSON to TypeScript converter. Paste any JSON object and get TypeScript interfaces generated instantly. Handles nested objects, arrays, optional fields, and null types. No signup required.
🍅 Free Pomodoro Timer
Free online Pomodoro timer. 25-minute focus sessions with 5-minute short breaks and 15-minute long breaks. Browser notifications, audio alerts, session tracking. No signup, no app download.
⏰ Free Cron Expression Generator
Free cron expression generator and parser. Build cron schedules visually — select minute, hour, day, month, and weekday — get the cron string instantly. Shows next 5 run times in plain English. No signup.
🎨 Free CSS Minifier & Beautifier
Free CSS minifier and beautifier. Paste your CSS to minify it for production or beautify it for readability. See byte savings instantly. No upload, no signup.
🔤 Free HTML Encoder / Decoder
Free HTML encoder and decoder. Convert special characters to HTML entities and back. Encode &, <, >, quotes, and all non-ASCII characters. No signup.
🔁 Free YAML to JSON Converter
Convert YAML to JSON and JSON to YAML — bidirectional with one swap click. Live conversion, validation errors with line numbers, and no data upload.
⏱️ Free Epoch & Unix Timestamp Converter
Free Unix epoch timestamp converter. Convert a Unix timestamp to a human-readable date (local, UTC, ISO 8601) and convert any date back to a timestamp. Auto-detects seconds, milliseconds, and microseconds. No signup.
🖼️ Free Image to Base64 Converter
Free image to Base64 / data URI converter. Drop in a PNG, JPG, WebP, GIF, or SVG and get the Base64 data URI plus ready-to-paste CSS background and HTML img snippets. Your image never leaves your browser. No signup.
🔀 Free JSON Diff & Compare
Free JSON diff and compare tool. Paste two JSON documents to see every added, removed, and changed value with its full key path. Key-aware comparison that ignores key order and whitespace. Runs entirely in your browser. No signup.
🗃️ Free SQL Formatter & Beautifier
Free SQL formatter and beautifier. Paste a messy query and get clean, indented SQL in 10 dialects including MySQL, PostgreSQL, SQLite, BigQuery, Snowflake, and T-SQL, with configurable keyword case and indentation. Runs entirely in your browser. No signup.
🧹 Free CSV Cleaner & Deduplicator
Free CSV cleaner and deduplicator. Remove duplicate rows, trim whitespace, and drop empty rows from any CSV in one pass. Proper parsing handles quoted fields, embedded commas, and line breaks. Runs 100% in your browser — your data is never uploaded. No signup.